 comput select keyword us word-frequenc analysi a statist base method automat identifi keyword machin-readabl text develop produc keyword list agre better composit list produc panel human index list produc statist criteria suggest better list produc individu panel member the method in-document word-occurr frequenc in-corpu rel occurr frequenc measur word each statist criterion compar perform human index rank correl statist the simpl word count superior suggest criteria - in-corpu rel occurr frequenc the test conduct 19 document deal subject inform scienc total 66 000 word occurr seventeen index repres center particip experi 